For generations, America has been thought of as the land of opportunity, a place where anyone who worked and studied hard could grow up to achieve any goal they set for themselves.

That idea has had especially strong roots in Illinois, the “Land of Lincoln,” where a young man born in a log cabin on America’s frontier rose from rail-splitter to self-taught lawyer and president of the United States.

But a new study suggests that the American dream is still more elusive for some people in Illinois than for others, and that the pathway up the economic ladder is not easily scaled.